The International Society for Clinical Densitometry (ISCD) is a not-for-profit multidisciplinary professional society with a mission to advance excellence in the assessment of skeletal health. This is accomplished by improving knowledge and quality of densitometry among healthcare professionals, educating and certifying clinicians and technologists, increasing patient awareness and access to densitometry, and supporting clinical and scientific advances in the field.

With the evolution of bone densitometry, differences in technologies, acquisition techniques, reference databases, reporting methods, and terminology have developed. These differences may have adverse effects on patient care and the exchange of scientific information. To address these issues, the ISCD periodically holds Position Development Conferences, a process whereby an international panel of experts makes recommendations based on reviews of the scientific literature by task forces associated with the ISCD Scientific Advisory Committee. Recommendations that are approved by the ISCD Board of Directors become Official Positions of the ISCD.

All ISCD Official Positions are for worldwide application except where otherwise noted.

2010 Official Positions of the ISCD/IOF on the Interpretation and Use of FRAX in Clinical Practice

The International Society for Clinical Densitometry (ISCD) and the International Osteoporosis Foundation (IOF) convened the FRAX® Position Development Conference (PDC) in Bucharest, Romania, on November 14, 2010, following a two-day joint meeting of the ISCD and IOF on the “Interpretation and Use of FRAX® in Clinical Practice”. These three days of critical discussion and debate, led by a panel of international experts from ISCD, IOF and by dedicated task forces, have clarified a number of important issues pertaining to the interpretation and implementation of FRAX® in clinical practice. The Official Positions resulting from the PDC are intended to enhance quality and clinical utility of fracture risk assessment worldwide. Since the field of skeletal assessment is new and evolving rapidly, some clinically important issues addressed at the PDCs are not associated with robust medical evidence. Accordingly, some Official Positions are based largely on expert opinion. Despite limitations inherent in any process such as this, ISCD and IOF believe it is important to provide clinicians and technologists with the best distillation of current knowledge in the discipline of bone densitometry and provide guidance to the scientific community on where further research is needed to resolve areas of ambiguity and/or ongoing controversy.

2007 ISCD Official Positions

These are the Official Positions of the ISCD as updated in 2007. The Official Positions that are new or revised since 2005 are in bold type. These Official Positions may also be viewed as a PDF file (link below) and all members will receive a printed copy of the 2007 Official Positions brochure when available. Additional copies of the brochure will be available through the ISCD BoneYard as soon as they are published. Included in the revisions this year are the addition of the Pediatric Official Positions. Click the link below to go directly to that section of the Official Positions text.

the North American Menopause Society (NAMS) (endorsement of sections pertaining to the menopausal woman)

National Osteoporosis Foundation (NOF) (*see footnote below)

* NOF has endorsed FRAX™, from the WHO, which incorporates a single reference population, the NHANES III female Caucasian database, for assessing 10 year absolute fracture risk in both genders. NOF believes more data are required in order to determine whether a single, female Caucasian reference database should be used for diagnostic T-score determinations in both genders or whether the male reference database is the preferred database for diagnostic purposes in men.

Women during the menopausal transition with clinical risk factors for fracture, such as low body weight, prior fracture, or high-risk medication use.

Men aged 70 and older.

Men under age 70 with clinical risk factors for fracture.

Adults with a fragility fracture.

Adults with a disease or condition associated with low bone mass or bone loss.

Adults taking medications associated with low bone mass or bone loss.

Anyone being considered for pharmacologic therapy.

Anyone being treated, to monitor treatment effect.

Anyone not receiving therapy in whom evidence of bone loss would lead to treatment.

Women discontinuing estrogen should be considered for bone density testing according to the indications listed above.

Reference Database for T-Scores

Use a uniform Caucasian (non-race adjusted) female normative database for women of all ethnic groups.*

Use a uniform Caucasian (non-race adjusted) male normative database for men of all ethnic groups.*

The NHANES III database should be used for T-score derivation at the hip regions.

*Note: Application of recommendation may vary according to local requirements.

Central DXA for Diagnosis

The WHO international reference standard for osteoporosis diagnosis is a T-score of -2.5 or less at the femoral neck.

The reference standard from which the T-score is calculated is the female, white, age 20-29 years, NHANES III database

Osteoporosis may be diagnosed in postmenopausal women and in men age 50 and older if the T-score of the lumbar spine, total hip, or femoral neck is -2.5 or less:*

In certain circumstances the 33% radius (also called 1/3 radius) may be utilized

*Note: Other hip regions of interest, including Ward’s area and the greater trochanter, should not be used for diagnosis. Application of recommendation may vary according to local requirements.

Skeletal sites to measure

Measure BMD at both the PA spine and hip in all patients

Forearm BMD should be measured under the following circumstances:

Hip and/or spine cannot be measured or interpreted.

Hyperparathyroidism

Very obese patients (over the weight limit for DXA table)

Spine Region of Interest (ROI)

Use PA L1-L4 for spine BMD measurement

Use all evaluable vertebrae and only exclude vertebrae that are affected by local structural change or artifact. Use three vertebrae if four cannot be used and two if three cannot be used

BMD based diagnostic classification should not be made using a single vertebra.

If only one evaluable vertebra remains after excluding other vertebrae, diagnosis should be based on a different valid skeletal site

Anatomically abnormal vertebrae may be excluded from analysis if:

They are clearly abnormal and non-assessable within the resolution of the system; or

There is more than a 1.0 T-score difference between the vertebra in question and adjacent vertebrae

When vertebrae are excluded, the BMD of the remaining vertebrae is used to derive the T-score

The lateral spine should not be used for diagnosis, but may have a role in monitoring

Hip ROI

Use femoral neck, or total proximal femur whichever is lowest.

BMD may be measured at either hip

There are insufficient data to determine whether mean T-scores for bilateral hip BMD can be used for diagnosis

The mean hip BMD can be used for monitoring, with total hip being preferred

Forearm ROI

Use 33% radius (sometimes called one-third radius) of the non-dominant forearm for diagnosis. Other forearm ROI are not recommended

Fracture Risk Assessment

A distinction is made between diagnostic classification and the use of BMD for fracture risk assessment.

For fracture risk assessment, any well-validated technique can be used, including measurements of more than one site where this has been shown to improve the assessment of risk.

Use of the Term “Osteopenia”

The term “osteopenia” is retained, but “low bone mass” or “low bone density” is preferred.

People with low bone mass or density are not necessarily at high fracture risk.

BMD Reporting in Postmenopausal Women and in Men Age 50 and Older

T-scores are preferred.

The WHO densitometric classification is applicable.

BMD Reporting in Females Prior to Menopause and in Males Younger Than Age 50

Z-scores, not T-scores, are preferred. This is particularly important in children.

A Z-score of -2.0 or lower is defined as “below the expected range for age”, and a Z-score above -2.0 is “within the expected range for age.”

Osteoporosis cannot be diagnosed in men under age 50 on the basis of BMD alone.

The WHO diagnostic criteria may be applied to women in the menopausal transition.

Z-Score Reference Database

Z-scores should be population specific where adequate reference data exist. For the purpose of Z-score calculation, the patient’s self-reported ethnicity should be used.

Serial BMD Measurements

Serial BMD testing can be used to determine whether treatment should be started on untreated patients, because significant loss may be an indication for treatment.

Serial BMD testing can monitor response to therapy by finding an increase or stability of bone density.

Serial BMD testing can evaluate individuals for non-response by finding loss of bone density, suggesting the need for reevaluation of treatment and evaluation for secondary causes of osteoporosis.

Follow-up BMD testing should be done when the expected change in BMD equals or exceeds the least significant change (LSC).

Intervals between BMD testing should be determined according to each patient’s clinical status: typically one year after initiation or change of therapy is appropriate, with longer intervals once therapeutic effect is established.

In conditions associated with rapid bone loss, such as glucocorticoid therapy, testing more frequently is appropriate.

Phantom Scanning and Calibration

The Quality Control (QC) program at a DXA facility should include adherence to manufacturer guidelines for system maintenance. In addition, if not recommended in the manufacturer protocol, the following QC procedures are advised:

Perform periodic (at least once per week) phantom scans for any DXA system as an independent assessment of system calibration.

Plot and review data from calibration and phantom scans.

Verify the phantom mean BMD after any service performed on the densitometer.

Establish and enforce corrective action thresholds that trigger a call for service.

Maintain service logs.

Comply with government inspections, radiation surveys and regulatory requirements.

Precision Assessment

Each DXA facility should determine its precision error and calculate the LSC.

The precision error supplied by the manufacturer should not be used.

If a DXA facility has more than one technologist, an average precision error combining data from all technologists should be used to establish precision error and LSC for the facility, provided the precision error for each technologist is within a pre-established range of acceptable performance.

Every technologist should perform an in vivo precision assessment using patients representative of the clinic’s patient population.

Each technologist should do one complete precision assessment after basic scanning skills have been learned (e.g., manufacturer training) and after having performed approximately 100 patient-scans.

A repeat precision assessment should be done if a new DXA system is installed.

A repeat precision assessment should be done if a technologist’s skill level has changed.

Calculate the root mean square standard deviation (RMS-SD) for the group

Calculate LSC for the group at 95% confidence interval

The minimum acceptable precision for an individual technologist is:

Lumbar Spine: 1.9% (LSC=5.3%)

Total Hip: 1.8% (LSC=5.0%)

Femoral Neck: 2.5% (LSC=6.9%)

Retraining is required if a technologist’s precision is worse than these values

Precision assessment should be standard clinical practice. Precision assessment is not research and may potentially benefit patients. It should not require approval of an institutional review board. Adherence to local radiologic safety regulations is necessary. Performance of a precision assessment requires the consent of participating patients.

Cross-Calibration of DXA Systems

When changing hardware, but not the entire system, or when replacing a system with the same technology (manufacturer and model), cross-calibration should be performed by having one technologist do 10 phantom scans, with repositioning, before and after hardware change.

If a greater than 1% difference in mean BMD is observed, contact the manufacturer for service/correction

When changing an entire system to one made by the same manufacturer using a different technology, or when changing to a system made by a different manufacturer, one approach to cross-calibration is:

Scan 30 patients representative of the facility’s patient population once on the initial system and then twice on the new system within 60 days

A statement about fracture risk. Any use of relative fracture risk must specify the population of comparison (e.g., young- adult or age-matched). The ISCD favors the use of absolute fracture risk prediction when such methodologies are established.

A general statement that a medical evaluation for secondary causes of low BMD may be appropriate.

Recommendations for the necessity and timing of the next BMD study.

Follow-Up DXA Report

Statement regarding which previous or baseline study and ROI is being used for comparison.

Statement about the LSC at your facility and the statistical significance of the comparison.

Report significant change, if any, between the current and previous study or studies in g/cm2 and percentage.

Comments on any outside study including manufacturer and model on which previous studies were performed and the appropriateness of the comparison.

The following general recommendations for QCT, pQCT, QUS, and pDXA are analogous to those defined for central DXA technologies. Examples of technical differences amongst devices, fracture prediction ability for current manufacturers and equivalence study requirements are provided in the full text documents printed in the Journal of Clinical Densitometry.

Bone density measurements from different devices cannot be directly compared.

Different devices should be independently validated for fracture risk prediction by prospective trials, or by demonstration of equivalence to a clinically validated device.

T-scores from measurements other than DXA at the femur neck, total femur, lumbar spine, or one-third (33%) radius cannot be used according to the WHO diagnostic classification because those T-scores are not equivalent to T-scores derived by DXA.

Device-specific education and training should be provided to the operators and interpreters prior to clinical use.

Limitations of the test including a statement that the WHO diagnostic classification cannot be applied to T-scores obtained from QCT, pQCT, QUS, and pDXA (other than one-third (33%) radius) measurements

Clinical risk factors

Fracture risk estimation

A general statement that a medical evaluation for secondary causes of low BMD may be appropriate

Recommendations for follow-up imaging

Note: A list of appropriate technical items is provided in the QCT and pQCT sections of the full text documents printed in the Journal of Clinical Densitometry.

With single-slice QCT, L1-L3 should be scanned; with 3D QCT, L1-L2 should be scanned

Fracture Prediction

Spinal trabecular BMD as measured by QCT has at least the same ability to predict vertebral fractures as AP spinal BMD measured by central DXA in postmenopausal women. There is lack of sufficient evidence to support this position for men

There is lack of sufficient evidence to recommend spine QCT for hip fracture prediction in either women or men

pQCT of the forearm at the ultra-distal radius predicts hip, but not spine, fragility fractures in postmenopausal women. There is lack of sufficient evidence to support this position for men

Therapeutic Decisions

Central DXA measurements at the spine and femur are the preferred method for making therapeutic decisions and should be used if possible. However, if central DXA cannot be done, pharmacologic treatment can be initiated if the fracture probability, as assessed by QCT of the spine or pQCT of the radius using device specific thresholds, and in conjunction with clinical risk factors, is sufficiently high

Monitoring

Trabecular BMD of the lumbar spine measured by QCT can be used to monitor age-, disease-, and treatment-related BMD changes

Trabecular and total BMD of the ultra-distal radius measured by pQCT can be used to monitor age-related BMD changes

Reporting

For QCT using whole body CT scanners the following additional technical items should be reported:

Tomographic acquisition and reconstruction parameters

kV, mAs

Collimation during acquisition

Table increment per rotation

Table height

Reconstructed slice thickness, reconstruction increment

Reconstruction kernel

For pQCT using dedicated pQCT scanners, the following additional technical items should be reported:

Tomographic acquisition and reconstruction parameters

Reconstructed slice thickness

Single / multi-slice acquisition mode

Length of scan range in multi-slice acquisition mode

QUS

Acquisition

The only validated skeletal site for the clinical use of QUS in osteoporosis management is the heel

Fracture Prediction

Validated heel QUS devices predict fragility fracture in postmenopausal women (hip, vertebral, and global fracture risk) and men over the age of 65 (hip and all non-vertebral fractures), independently of central DXA BMD

Discordant results between heel QUS and central DXA are not infrequent and are not necessarily an indication of methodological error

Heel QUS in conjunction with clinical risk factors can be used to identify a population at very low fracture probability in which no further diagnostic evaluation may be necessary. (Examples of device-specific thresholds and case findings strategy are provided in the full text documents printed in the Journal of Clinical Densitometry.)

Therapeutic Decisions

Central DXA measurements at the spine and femur are preferred for making therapeutic decisions and should be used if possible. However, if central DXA cannot be done, pharmacologic treatment can be initiated if the fracture probability, as assessed by heel QUS, using device specific thresholds and in conjunction with clinical risk factors, is sufficiently high. (Examples of device-specific thresholds are provided in the full text documents printed in the Journal of Clinical Densitometry.)

Monitoring

QUS cannot be used to monitor the skeletal effects of treatments for osteoporosis

pDXA

Fracture Prediction

Measurement by validated pDXA devices can be used to assess vertebral and global fragility fracture risk in postmenopausal women, however its vertebral fracture predictive ability is weaker than central DXA and heel QUS. There is lack of sufficient evidence to support this position for men

Radius pDXA in conjunction with clinical risk factors can be used to identify a population at very low fracture probability in which no further diagnostic evaluation may be necessary. (Examples of device-specific thresholds and case findings strategy are provided in the full text documents printed in the Journal of Clinical Densitometry.)

Diagnosis

TheWHO diagnostic classification can only be applied to DXA at the femur neck, total femur, lumbar spine and the one-third (33%) radius ROI measured by DXA or pDXA devices utilizing a validated young-adult reference database

Therapeutic Decisions

Central DXA measurements at the spine and femur are the preferred method for making therapeutic decisions and should be used if possible. However, if central DXA cannot be done, pharmacologic treatment can be initiated if the fracture probability, as assessed by radius pDXA (or DXA) using device specific thresholds and in conjunction with clinical risk factors, is sufficiently high. (Examples of device-specific thresholds are provided in the full text documents printed in the Journal of Clinical Densitometry.)

Monitoring

pDXA devices are not clinically useful in monitoring the skeletal effects of presently available medical treatments for osteoporosis

Skeletal Health Assessment In Children and Adolescents
(Males and Females ages 5-19)

Fracture Prediction and Definition of Osteoporosis

Fracture prediction should primarily identify children at risk of clinically significant fractures, such as fracture of long bones in the lower extremities, vertebral compression fractures, or two or more long-bone fractures of the upper extremities.

The diagnosis of osteoporosis in children and adolescents should NOT be made on the basis of densitometric criteria alone.

The diagnosis of osteoporosis requires the presence of both a clinically significant fracture history and low bone mineral content or bone mineral density.

A clinically significant fracture history is one or more of the following:

Long bone fracture of the lower extremities

Vertebral compression fracture

Two or more long-bone fractures of the upper extremities

Low bone mineral content or bone mineral density is defined as a BMC or areal BMD Z-score that is less than or equal to -2.0, adjusted for age, gender and body size, as appropriate.

DXA Assessment in Children and Adolescents With Disease That May Affect the Skeleton

DXA measurement is part of a comprehensive skeletal health assessment in patients with increased risk of fracture.

Therapeutic interventions should not be instituted on the basis of a single DXA measurement.

When technically feasible, all patients should have spine and total body less head (TBLH) BMC and areal BMD measured

Prior to initiation of bone-active treatment.

To monitor bone-active treatment in conjunction with other clinical data.

In patients with primary bone diseases or potential secondary bone diseases (e.g., due to chronic inflammatory diseases, endocrine disturbances, history of childhood cancer, or prior transplantation (non-renal)), spine and TBLH BMC and areal BMD should be measured at clinical presentation.

In patients with thalassemia major, spine and TBLH BMC and areal BMD should be measured at fracture presentation or at age 10 years, whichever is earlier.

In children with chronic immobilization (e.g., cerebral palsy) spine and TBLH BMC and areal BMD should be measured at fracture presentation.

DXA should not be performed if contractures prevent the safe and appropriate positioning of the child.

The minimum time interval for repeating a bone density measurement to monitor treatment with a bone-active agent or disease processes is six months.

DXA Interpretation and Reporting in Children and Adolescents

DXA is the preferred method for assessing BMC and areal BMD.

The PA spine and TBLH are the most accurate and reproducible skeletal sites for performing BMC and areal BMD measurements.

Soft tissue measures in conjunction with whole body scans may be helpful in evaluating patients with chronic conditions associated with malnutrition (such as anorexia nervosa, inflammatory bowel disease, cystic fibrosis), or with both muscle and skeletal deficits (such as idiopathic juvenile osteoporosis).

The hip (including total hip and proximal femur) is not a reliable site for measurement in growing children due to significant variability in skeletal development and lack of reproducible ROI.

In children with linear growth or maturational delay, spine and TBLH BMC and areal BMD resultsshould be adjusted for absolute height or height age, or compared to pediatric reference data that provide age-, gender-, and height-specific Z-scores.

An appropriate reference data set must include a sample of the general healthy population sufficiently large to characterize the normal variability in bone measures that takes into consideration gender, age, and race/ethnicity.

When upgrading densitometer instrumentation or software, it is essential to use reference data valid for the hardware and software technological updates.

Baseline DXA reports should contain the following information:

DXA manufacturer, model, and software version

Referring physician

Patient age, gender, race/ethnicity, weight, and height

Relevant medical history including previous fractures

Indication for study

Bone age results, if available

Technical quality

BMC and areal BMD

BMC and areal BMD Z-score

Source of reference data for Z-score calculations

Adjustments made for growth and maturation

Interpretation

Recommendations for the necessity and timing of the next DXA study are optional

Serial DXA testing

Should be done only when the expected change in areal BMD equals or exceeds the LSC

Serial DXA reports should include the same information as for baseline testing, but additionally include:

Indications for follow-up scan

Comparability of studies

Interval changes in height and weight

BMC and areal BMD Z-scores adjusted or unadjusted for height or other adjustments

Percent change in BMC and areal BMD and interval change in Z-scores

Recommendations for the necessity and timing of the next BMD study are optional

Accurate interpretation of serial DXA results requires knowledge of the LSC for all sites measured and for all technologists at the DXA testing facility.

Terminology

T-scores should not appear in pediatric DXA reports.

The term “osteopenia” should not appear in pediatric DXA reports.

The term “osteoporosis” should not appear in pediatric DXA reports without knowledge of clinically significant fracture history.

“Low bone mineral content or bone mineral density for chronologic age” is the preferred term when BMC or BMD Z-scores are less than or equal to -2.0.

pQCT in Children and Adolescents

Reference data are not sufficient for the clinical use of pQCT for fracture prediction or diagnosis of low bone mass.

When the forearm is measured, the non-dominant forearm should be used.

Measurements sites should include the metaphysis and diaphysis.

Determination of the precision error, LSC, and monitoring time interval should be performed as described for DXA.

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